It is known that the ketones of formula (I) can be used as intermediates for the preparation of isoflavone derivatives (see e.g. HU PS No. 163,515) as well as anabolics since they effect metabolism.
From an industrial point of view those processes are the most advantageous wherein resorcinol is used as starting material, e.g. the desired product may be obtained according to the Houben-Hoesch reaction: wherein the resorcinol is reacted in anhydrous medium with benzyl cyanide in the presence of dry hydrogen chloride gas and anhydrous tin chloride (see e.g. J. Chem. Soc. /1923/, 404 and J. Am. Chem. Soc. 48, 1926, 791). The yield in this reaction is 50% and the drawback of this process is that the hydrolysis of the "ketimine" derivate intermediate is a very corrosive procedure.
Alternatively 2-hydroxy-4-n-butoxy-phenyl-benzyl ketone or 4-hydroxy-2-n-butoxy-phenyl-benzyl ketone may be obtained when reacting the mono-n-butyl ether of resorcinol with phenyl-acetyl-chloride in the presence of pyridine, then removing pyridine by distillation, dissolving the residue in ether, extracting the solution with hydrogen chloride several times, removing the ether by distillation, thereafter treating the 1-phenyl-acetyloxy-4-n-butyloxy-phenol thus obtained in nitrobenzene with aluminum chloride and steam distilling the mixture thus obtained (see Example 7 of HU PS No. 168,744). The starting material of the first step, i.e. the mono-n-butyl ether of resorcinol, can be obtained e.g. when reacting resorcinol with n-butyl bromide in the presence of dimethyl formamide. Regarding that from resorcinol diether derivatives may also be formed, in order to obtain an end product of good quality, the monoethers have to be purified before the second reaction step.
The analogous phenol compound can be prepared by the known, so called Bouveault reaction too, wherein 2 moles of anhyrous aluminium chloride are reacted with phenol. In the first step of this reaction phenoxy-aluminium dichloride forms while hydrogen chloride gas is released. In the second reaction step said phenoxy-aluminium dichloride is then reacted with the acid chloride derivative in the presence of a further mole of aluminium chloride (Olah, Gy:Friedel Crafts and related reactions, Vol. I, page 97, 1963).
The drawbacks of these known processes are as follows: